【正文】 the field of. Each kind of wave may use the trigonometric function equation. Can produce a variety of waveforms, such as the triangle wave, sawtooth wave, rectangular wave (including square wave ), sine wave circuit is called the function signal generator. Function signal generator in electric circuit experiment and the equipment examination has a very wide range of uses. For example, in munication, broadcasting, television system, needs the radio frequency ( HF) emission, the radio wave is the carrier, the audio frequency ( low frequency ), the video signal or pulse signal to carry out, will need to be able to produce the high frequency oscillator. In industry, agriculture, biomedical and other fields, such as highfrequency induction heating, smelting, quenching, ultrasound, magic resonance imaging, required power big or small, or high or low frequency oscillator. This paper design a signal generator, and AT89C51 is used as a control microcontroller core, It can generate sine wave, square wave, triangle wave through the method of program design , and the simulation by the puter soft ware Proteus is been done , and those results consistent with the theory． converting a digital signal into an analog signal through the D/A converter ,and ultimately displayed by the oscilloscope. Through the button to control the options of waveform types and can change frequency ,amplitude and frequency of the waveform can be arbitrarily changed within a certain range. The design eliminates the defect of waveform distortion which produced by the dispersion of the ponents which exist in the traditional signal generator. Its design is simple,inexpensive,stable and can be used in a variety of occasions that require low frequency signal source,it has practical value. 【 keywords】 Signal Generator D / A converter AT89C51 Frequency Margin 7 目錄 第一章 緒論 ..................................................................................................................... 4 課題研究的動(dòng)態(tài)和意義 ........................................................................................... 4 單片機(jī)概述 ................................................................................................................ 4 信號發(fā)射器分類 ........................................................................................................ 4 設(shè)計(jì)任務(wù)和要求 ........................................................................................................ 5 第二章 方案的設(shè)計(jì)與選擇 ................................................................................................ 5 方案的比較 ............................................................................................................... 5 設(shè)計(jì)原理 ................................................................................................................... 5 設(shè)計(jì)功能 ................................................................................................................... 6 第三章 主要電路元器件介紹 ............................................................................................ 6 AT89C51 單片機(jī)簡介 ................................................................................................ 6 DAC0832 簡介 ............................................................................................................ 8 第四章 硬件實(shí)現(xiàn)和 單元電路設(shè)計(jì) .................................................................................... 9 硬件原理框圖 ........................................................................................................... 9 復(fù)位電路 ................................................................................................................. 10 D/A 轉(zhuǎn)換電路 ...........................................................................................................11 按鍵接口電路 ......................................................................................................... 12 時(shí)鐘模塊設(shè)計(jì) ......................................................................................................... 12 顯示模塊設(shè)計(jì) ......................................................................................................... 13 第五章 軟件設(shè)計(jì) ............................................................................................................ 14 程序流程圖 ............................................................................................................. 14 初始化程序 .............................................................................................................. 15 鍵掃描程序 .............................................................................................................. 15 波形產(chǎn)生程序 .......................................................................................................... 16 波形仿真 .................................................................................................................. 17 第六章安裝調(diào)試和問題解決 ............................................................................................ 21 調(diào)試過程 .................................................................................................................. 21 出現(xiàn)問題與解決方法 .............................................................................................. 21 實(shí)驗(yàn)總結(jié) ............................................................................................................................ 22 致謝 .................................................................................................................................... 22 參考文獻(xiàn) ............................................................................................................................ 22 附錄 1 電路原理圖 ........................................................................................................... 23 附錄 2 源程序 ................................................................................................................... 23 7